OPTIONS

The OPTIONS method is used to describe the communication options for the target resource.

Usage

It is heavily used in CORS (Cross-Origin Resource Sharing) as a “preflight” request to determine if the actual request is safe to send.

CORS Preflight Example

Browsers emit an OPTIONS request automatically when a cross-origin request requires it (e.g. using custom headers).

OPTIONS /resource HTTP/1.1
Host: api.example.com
Origin: https://example.com
Access-Control-Request-Method: POST

The server responds with Access-Control-Allow-Methods and other relevant CORS headers.